Auxiliary telegraph signal transmitter



prfl W, 1941. J. A. SPENCER AUXILIARY TELEGRAPH SIGNAL TRANSMITTER FiledMay 28, 1938 INVENTOR. JAMES Z ATTORNEY.

Q W &

m 2 WEQ i 6 w Q1:353:532E3;222: 2 21 2 1 t V NE: SN

Patented Apr. 15, 1941 AUXILIARY TELEGRAPH SIGNAL TRANSMITTER James A.Spencer, Teaneck, N. J., assignor to Radio Corporation of America, acorporation of Delaware Application May 28, 1938, Serial No. 210,669

12 Claims.

This invention relates generally to printing telegraph systems andparticularly to devices for transmitting auxiliary signals independentlyof the traific signals which normally are transmitted under control of aperforated tape. The invention as herein shown and described isparticularly applicable to the requirements of simplex and synchronousmultiplex telegraph systems. The preferred embodiment of my invention isalso adapted for use in connection with the so-called Z-unit equallength printer code. This code is advantageously used on radio telegraphchannels for the reason that it provides a basis for the automaticdetection of errors due to the mutilation of signals.

Details of a system for automatic error detection of mutilated signalsare shown and described in U. S. Patent 2,183,147, granted December 12,1939, to John B. Moore and Richard E. Mathes. According to the teachingsof Moore and Mathes each of the code combinations of a 7-unit code or anS-unit code is characterized as having a fixed ratio between the numberof marking units and the number of spacing units.

It is one of the objects of my invention to provide an idle-timesignalling device which may be automatically put into service duringperiods of any considerable duration between successive messagetransmissions whereby the radio channel between stations may bemonitored and held in readiness for further message transmissions,without the necessity for reestablishing. synchronism between thesending and receiving apparatus.

It is a further object of my invention to provide facilities for thetransmission of auxiliary signals independently of the ordinarytape-controlled operation of the channel as in synchronous multiplexwork.

These auxiliary signals are sometimes termed service signals and areuseful for indicating starting and stopping periods in the transmissionof trafiic signals as well as in order to indicate departures fromnormal conditions of transmission and reception. e

Other objects and advantages of my invention will be brought out in thedetailed description to follow.

My invention will be better understood by reference to the accompanyingdrawing which comprehends one figure only. This figure shows a schematiccircuit diagram comprising means for transmitting auxiliary servicesignals as well as means for the transmitting of an idle-time signal.

j the outgoing line.

rings #2 and #4.

Referring to the drawing, I show therein an arrangement of signallingelements I to I, inclusive, which are included within the broken linerectangle T, these elements being arranged as contact tongues 8 whichare positionable in contact either with positively or with negativelypolarized feeder contacts 9 and i0, respectively. The tongues 8 arearranged to be set in their alternative contacting positions in responseto the operation of a set of seeker pins which are controlled byperforations in the transmitting tape. According to a recently adoptedpractice in the transmission of printing telegraph signals, the messageto be transmitted is first perforated in 7-unit code signals on a stripof paper tape which is fed at a cyclic rate to the transmitter.Different code combinations are thus set up on the tape-controlledtongues 8 for transmission of marking or spacing signalling elements ineach of the seven positions of a uniform length code signal. Theparticular code combination required for transmission of a givencharacter is thus communicated to the transmitting segments of amultiplex distributor.

Such a distributor is shown generally at D and has preferably fourrings. Ring #9 comprises individual code element segments for aplurality of channels of the multiplex system. Ring #3 is merely acollector ring connected to The brush ll bridges the segments of ring #Isuccessively across to ring #3. Ring #2 has segments corresponding tothose of ring #I, while ring #4 is a collector ring cooperatingtherewith. Brush l2 bridges The brushes H and I 2 are insulated from oneanother but are mounted for synchronous rotation, being preferablydriven by a synchronous motor which is held in step with other portionsof the multiplex telegraph system, in accordance with any of the usualmethods of synchronization. The purpose of the segments in ring #2 willbe explained later.

Since there are two main functions to be performed by the auxiliarysignalling device of my invention, I will first describe how anidle-time signal may be transmitted, and subsequently I will describehow any one of a plurality of service signals may be transmitted.

Certain of the code signalling tongues 8 are connected through contactsI3, l4 and I5 of a relay l6 and thence through other contacts of theservice signalling device, which is camoperated, to the respectivesegments of the distributor ring #I to which they are appropriate. Onlyone of the tongues 8, namely, that which is in position 1, leadsdirectly to its segment i in ring #1 of the distributor. Code signallingtongue 8 in position 2 is connected through a back contact andarmature-operated spring l3, and thence through mutually contactingsprings H and M3 to segment 2 in distributor ring #1. In code signallingposition 3 the tongue 8 is connected to mutually contacting springs Hiand 20 and thence to segment 3 in ring #I of the distributor. Thesignalling tongues 8 in positions 4 and 5 are likewise connected totheir respective segments in the distributor ring #I, but by way ofmutually contacting springs 2| and 22 in the case of the tongue 8 inposition 4, whereas the tongue 8 in position 6 is connected throughmutually contacting springs 25 and 25 to distributor segment 6. Theconnections of the tongues 8 in positions 5 and I, respectively, are

similar to that of the tongue 8 in position 2.v In

other words, the conductive circuits from these tongues 8 to theirrespective segments comprise back contacts and operating contacts M andon relay l6, as well as mutually contacting springs 23 and 24 in the onecase, and 2'! and 23 in the other case.

When traffic signals are being sent, the perforated tape is fed at acyclic rate through the transmitter whereby the transmitter tongues 8are controlled and the marking and spacing (or positive and negative)signals are thus communicated to the segments of the distributor ring#I. These signals are then sent out over the synchronous multiplexchannel in accordance with the rotation of the brush II. The transmitterT is, therefore, normally uninfiuence d by either the relay [6 or by thecontacts I! to 23, inclusive, which latter contacts are designed fortransfer of operating control from the transmitter T to the auxiliarysignalling device whenever it is required that a service signal shall betransmitted.

In positions 2, 5 and 1 the transmitting tongues 8 may at times bedisconnected from their respective distributor segments, as when therelay i6 is operated. The purpose of the relay I5 is to make it possibleto repeatedly transmit an idle-time signal. The composition of thesignal itself is of importance in carrying out my invention. Thus, itwill be noted that t consists of three marking elements in positions 2,5 and I of the uniform length code signal. These marking elements arecommunicated to distributor segments 2, 5 and I on ring #l by virtue ofthe fact that upon energizing the relay 16 its operating contacts I3, l4and I5 are respectively fed with positive (marking) current from thesame source B which feeds the contacts of the transmitter T. This codecombination consisting of marking elements in positions 2, 5 and I hasbeen chosen to indicate that the channel is being maintained ready forservice. but the signal itself is ineffective in selecting any of thetype bars of a receiving printer such as would be operated in responseto traflic signals at the receiving end of the multiplex channel. In thecase of failure of the channel itself these idle-tirne signals would notbe received. or else they might be received in a mutilated form. Ineither case the printer is adapted to make a peculiar response such asto designate the interruption of service on that particular channel.Immediately upon reception of such a failure indication steps can betaken at the receiving end to notify the transmitting operator or othersso that the faults may be corrected,

or so that the transmission of traffic signals may be postponed untilsatisfactory service conditions are restored.

The idle-time signals may be transmitted at will by energizing the relay56 under control of a manual switch indicated generally at MS. Thisswitch comprises a manual lever 29 having thereon a device 38 whichengages with a contact spring 3| and. presses the latter against acompanion contact spring 32. The winding of the relay It may be fed withpositive potential from the source B by Way of a resistor 33. The returncircuit for the relay winding is through contacts 32 and 3| to thenegative side of the source B. The manual switch MS is mechanicallylinked to the operating mechanism of the transmitter T in such a mannerthat the contacts 3i and 32 will be closed only upon completion of thetransmission of a given character signal. The details of thisassociation of the manual switch MS and the operating parts of thetransmitter are not herein shown since they have been used in the priorart.

I have, however, shown an operating magnet 34 by which the seeker pins Hand the tape feed mechanism, including the sprocket Wheel 35, aresynchronously operated. The timing of operation of the magnet 36 isobtained by feeding positive current to ring #4 and across brush I2preferably to segments 8, 9 and iii (of ring #2) which are connected incommon to conductor 36 leading to contacts 31 and 33 of a differentialrelay Ml. Contact 38 feeds to one of the windings of relay 41) andthence to the windings of relay 34 over the common conductor 6!. Theother terminal of the windings of operating magnet 34 is connected tothe negative side of the source B.

The relay 4B is designed to operate when one only of its windings isenergized, but will not cperate when both windings are energized, sincethe direction of current therein as arranged to neutralize themagnetization of the relay core. Normally, then, the local impulseswhich are transmitted over segments 8, 9 and H) to conduotor 36 will bebranched so that both windings of relay 40 will be simultaneously andequally energized. The branch for the left-hand Winding of relay 46 maybe traced through conductor 42 to contact 43 and a companion contact 4%and thence over conductor (*5 to mutually engaging contacts 46 and M andto the left relay winding 40. The circuit just now traced may he openedupon the occurrence of either of two conditions. Under one of theseconditions the tape-slack between the perforator (not shown) and thesprocket Wheel 35 of the transmitter may be reduced to the point wherecontacts 46 and i! are opened. Only the right-hand winding of the relay40 will remain energized and hence this relay will pull up its armature:8 for engagement with contact spring 38. The spring combination 31, 38and 48 is of the make-before-break type. Consequently, the operatingmagnet 36 instead of being fed with positive impulses from ring #2 inthe distributor will now be fed with a steady current from the source Bover conductor 49, contacts 48 and 38, the right-hand winding of relayM1, and thence to the windings of operating magnet 34 to the negativeside of the source B. The operating magnet 34 will now be locked up andthe transmitter will wait until sufiicient slack in the tape is restoredso that contact may be made between springs 46 and 4'! for neutralizingthe magnetization of the windings in relay 40. Upon release of thearmature 48 normal transmitting conditions will be restored. Theinterruptions of transmission incident upon failure to feed thetransmitting tape as rapidly as the transmitter can use it are,generally speaking, of short duration and do not require thetransmission of idle-time signals for maintenance of service on thecommunications channel. Longer interruptions, however, which call forshutting down the transmitter, entail the setting of the manual switchMS so that cont-acts 3| and 32 will be closed and relay l6 operated.There is another function performed by the manipulation of the lever 29besides closing the contacts 3i and 32. It is to arrest the tape feedmechanism without mutilating the code elements set up b y the tongues 8.The mechanism for performing this function is not shown or describedherein because it is old in the art and is separate and distinct fromthe objects of my invention.

I will now describe a mechanism which is useful for the transmission ofspecial service signals.

To a certain extent this mechanism follows the teachings of the priorart, particularly as illustrated by United States Patent #1,2'75,559granted August 13, 1918, to W. A. I-Ioughtaling. However, there arecertain novel elements of construction residing in the mechanism asherein shown and described and these will be brought out moreparticularly in the claims to follow.

The special service signals to be transmitted by means of a supplementalsignalling device are those whereby any one or more taps of a bell maybe produced at the receiving end. Although the perforator keyboard isusually provided with a certain key for perforating a code signal thesignificance of which in the shift position is functional and results inthe ringing of a bell attached to the receiving printer, it is oftenrequired that the bell signal shall be transmitted independently of anyprepared code signals as perforated in the tape. Accordingly, I providea dialing member 50 for special transmission of a series of codesignals. The extent of movement of the dialing member 50 is determinedby placing ones finger in any one of the holes and drawing the membertoward oneself until the finger strikes a stationary stop The operatorthen withdraws his finger from the selected hole El and releases thedialing member to be restored to its normal position under the influenceof a coiled spring 6!], this spring having been wound by the previousmotion of manual dialing. A gear is loosely mounted on the shaft tilland has projecting therefrom a pivot pin for supporting a pawl 6| whichis adapted to engage with the teeth of a ratchet wheel 58 fixedlymounted on the shaft 51. The dialing member 56 and a switch-controllingdog 59 are also fixedly mounted on the shaft 51. During a dialingoperation the pawl 6i ratchets over the teeth of the ratchet wheel 58,but during the return motion of the shaft 51, the pawl 6| is engaged bya tooth of the ratchet wheel 58 and caused to rotate backward, withshaft 51 carrying its gear 56 and so imparting rotation to the pinion 54fixedly mounted on the shaft 53. This shaft 53 also carries a series ofcode impulsing cams C1 to C5, inclusive, and a ratchet wheel 55, allfixedly mounted thereon.

The cam shaft 53 can rotate only as permitted by the operation of anescapement whose arms 63a are integral with an armature 63 which ispositive under control of a pulsating magnet 62. The impulses foractuating the magnet 62 are derived from the source B fed throughdistributor ring #4, and across brush I2 to segments 8, 9 and ID of ring#2. This circuit may be further traced through conductors 36 and 42 tocontact springs 43, and 69 and thence to the windings of magnet 62 andfinally returning to the negative side of the source B.

The circuit just described is one which is formed upon manipulating thedial member 50, due to the fact that the dog 59 has been therebywithdrawn from pressure against the resilient contact spring 43. Thetension in this spring urges it, when released, away from contact withspring 44 and in contact with spring 69 which is in circuit with thewinding of magnet 62. The operating impulses from the distributor ring#2 are, therefore, transferred from the operating magnet 34 of thetransmitter to the escapement magnet 62 of the auxiliary signallingdevice.

Depending upon the hole 5| which is fingered, from one to five strokesof the bell will be produced at the receiver. However, it requires theshift signal, the bell signal, and the unshift signal for each stroke ofthe bell. Consequently, the code determining cams C1 to C5, inclusive,are provided for setting up these code signals and for transmitting thesame.

Upon each revolution of the brush 12 a single impulse will betransmitted tothe escapement magnet 62.. Consequently, successivesignals as set up on the peripheries of the cams C1C5 will betransmitted over the transmitting segments 2 to 1, inclusive, on ring #Iof the distributor C.

The cams C1 to C5, inclusive, are shown( in their normal or inactivepositions whereat each of the even-numbered contact springs I 8 to 23,in.- clusive, rests against its associated lower contact spring, therebeing a notch in each one of the cams for permitting this connection tobe made.

By rotating the cams through an arc of 18 which is the angle subtendedby one of the teeth of the ratchet wheel 55, it will be seen that raisedportions of cams C1, C2 and C3 come under their associated controlsprings I 8, 2|] and 22, respectively. At this step of the operationpositive (marking) current is fed from the source B through the uppercontacts with which the operating contacts I8, 20 and 24 are now in themake position and hence enabled to transmit current to segments 2, 3 and4, respectively, on distributor ring #I. This transmits the signal whichhas been arbitrarily chosen as the figure shift signal.

Art the next step of the escapement wheel 55 cams C2 and C5 are inposition for elevating their operating springs 20, 26 and 28, thereby toimpress positive current upon distributor segments 3, 6 and 7. This isthe composition of an arbitrarily chosen signal for the bell ringingfunction on the printer. The bell signal (following the shift signal)usually corresponds with the signal for the letter J; but, if preferred,it may be the same signal as chosen for the letter S, or any otherlower-case character on the keyboard.

In the next position of the escapement wheel 55, cams C2, C3 and C4 arein position to elevate their operating springs 20, 22 and 24,respectively, thereby to impress positive current upon distributorsegments 3, 4 and 5. This is a signal arbitrarily chosen to designatethe unshift function.

The steps of operation of the cams as thus far described are those whichwould be performed if the operator wished to transmit a single-strokebell signal. He does this by inserting his finger in the hole of thedialing member nearest the stop 52. The four steps necessary to transmitsuch a signal are, respectively, shift, bell, unshift and finally thenormally inactive position. When the number of strokes of the bell is tobe greater than one, the extent of motion of the dialing member 58 isdetermined by the hole 5! which is fingered by the operator, andaccordingly, any selected are of a revolution of the cams may betraversed for transmitting a proper sequence of signals necessary toproduce the desired number of taps of the bell. Usually from one to fivestrokes are sufficient for all of the usual service signals such asstart, re-run, re-punch, stop and regulate.

It should be noted particularly that the circuit diagram as shown issuch that certain series connections are formed through the trafiic codedetermining elements 8 of the transmitter T, through back contacts andoperating contacts of relay It, and thence through cam operated contactsof the auxiliary signalling device to the distributor segments. However,in code element position I a direct connection is made between the firstcode element tongue 8 and segment I on distributor ring #I. l

Furthermore, in code element positions 3, 4 and 6 there is no the relay[5, but these connections are directly from the tongues 8 through camoperating contacts to distributor segments 3, 4 and 6, respectively.

It is, of course, to be understood that this arrangement is arbitraryand that if the character designations of the different code signalswere to be altered, corresponding changes would be made in the circuitdiagram.

Reviewing the operation of my improved auxiliary telegraph signaltransmitter, it should be noted that the brushes I! and I2 are caused torotate over their respective distributor rings of each station. Thediagram shows two rings #l and #3 assigned to the signalling circuit.The additional rings #2 and #4 are required to perform the localfunctions as heretofore described. One of these local functions is tooperate the transmitter and the automatic control. The operatingimpulses are supplied to the magnet 34 and at times to the auxiliarysignalling device escapement magnet 62. The transfer of these impulsesis made by the off-normal switch whose dog 59 releases the spring 43whenever a dialing operation is made for transmitting a desired r numberof repetitions of the bell signal. At the time of this transfer ofoperating impulses the tension of the spring 43 is such as to urge itagainst contact spring 69 after opening the circuit between contactsprings 43 and 44.

It is clear from the above given description that in dialing to produceany number of strokes of the bell the cam shaft 53 will be rotatedthrough an are which is a corresponding multiple of 72. The outgoingsignals are impressed upon a synchronous multiplex channel under controlof the escapement whose armature 63 responds to the impulses applied tothe operating magnet 62 by the multiplex distributor brush l2. Therotation of the cams C1 to C5, inclusive, is, therefore, synchronizedwith the passage of the brush l2 over segments 8, 9 and is. Four stepsare. required for each stroke of the bell signals- Since there aretwenty teeth in the ratchet wheel 55 each transmission of the bellsignal represents need for including contacts of 1 of a revolution ofthe cams C1 to C5, inclusive. The peripheral characteristics of the camsC1 to C5 are, therefore, repeated every 72 of their circumference. Thisallows of repeating the bell signal five times with one revolution ofthe cam shaft 53.

During the transmission of the shift, the bell, and the unshift signals,it will, of course, be appreciated that the operation of the transmitterT is temporarily interrupted. This interruption is attained by openingcontacts 43 and 44 which are included in the circuit to the left-handwinding of relay 40. This causes the right-hand winding to act alone inlocking up the relay so as to deliver a steady current from the source Bthrough th armature 48 and its front contact 38, thence through theoperating winding of relay 4El and the windings of magnet 34 andreturning to the negative side of the source B.

When the dialing member 50 is released, the cam shaft revolves undertension of the spiral spring Bil, as previously mentioned, but only atthe impulsing cadence which is obtained by the passage of brush l2 overthe distributor segments 8, 9 and H) on ring #2, since the impulses soproduced serve to actuate the escapement magnet 62.

It may well be that certain of the segments in distributor ring #2 haveno connections thereto; nevertheless those segments which are tiedtogether are useful for maintaining a properly timed relation betweenthe transmitter-operating impulses appropriate to the different channelsof the multiplex system. Other devices (not shown) may also bemaintained in synchronism in accordance with the sweep of the brush [2over different segments of ring #2.

Thus, assuming that the transmitter T is assigned to channel A whosedistributor segments in ring #I are numbered I to 1, inclusive. Thensegments 8 to M may be considered as appropriate to channel B, whilesegments 15 to 2| are appropriate to channel C. The assignment ofsegments in ring #2 for correctly timing the action of differenttransmitter operating magnets (such as magnet 34) will be as follows:

Transmitter T for channel A uses segments 8, 9 and I9. Channel B usessegments !5, l6 and I1, while channel C uses segments l, 2 and 3. Bythis arrangement the seeker pins are withdrawn from the tape a momentfollowing the pick-up of the signals as determined by the setting of thecode element numbers I to l, inclusive (for channel A). With regard tothe other channels the corresponding operating magnets 34 are energized,for channel B, immediately after the pick-up of the code signals onsegments 8 to M, inclusive, of ring #I, and, for channel C, immediatelyafter the pick-up of code signals on segments l5 to 2|, inclusive.

It will be noted further that the operation of the idle-time signallingdevice is entirely independent of otoher mechanisms except that it isunder control of the manual switch MS, and when in service the operatingmagnet 34 for the transmitter on a given channel is locked up while thetape feeding mechanism is held inactive. It may be seen that within thecomplete multiplex system any one or more of the multiplex channels maybe shut down independently of the others. The idle-time signal will thenautomatically take the place of the traffic signals on such channels asare shut down. Transmission of the idle-time signals has a certain valueother than for differentiating between fades and spaces because whensignals are transmitted on each of plex printing telegraph system whichconnects transmitting and receiving stations over a radio channel.

Various modifications of the invention will doubtless suggest themselvesin view of the foregoing description; The scope of the invention is,therefore, to be considered as having as great breadth as is permittedby the claims.

I claim:

1. A telegraph transmitting system comprising a line, a code impulsedistributor having at least seven code-element circuit terminals andmeans for sequentially connecting the same to said line, transmittingmeans for impressing upon said terminals trafiic code signals of thetype wherein a fixed ratio is maintained between the number of markingelements and the number of spacing elements of each code signal, aperforated tape and tape feeding device for controlling saidtransmitting means, impulsing means associated with said distributor forproducing a step-by-step operation of said tape feeding device,manipulative means for starting and stopping said tape feeding device,and means under control of said manipulative means for causing anidle-time signal to be transmitted during relatively long inactiveperiods of said tape feeding device, said idle-time signal beingcharacterized by a number of marking and spacing impulses the ratiobetween which is the same as the afore-mentioned fixed ratio. r

2. A system in accordance with claim 1 and having means including aswitch operable under control of a predetermined tension on said tapefor arresting said tape feeding device.

3. In a telegraph transmitting system, a line,

i a distributor, a perforated tape transmitter operable to impress,7-unit code signals throughsaid distributor to said line, each of saidsignals being composed of marking and spacing units the nu-- mericalratio between which is uniformly fixed, means in circuit between saidtransmitter and said distributor for at times impressing an idletimesignal on said line, said idle-time signal being characterized byconformity of its marking and spacing units to said fixed ratio, andmanipulative means operable to shut down said transmitter and to renderthe idle-time signalling means operable thereafter. I

4. A system in accordance with claim 3 and including means in circuitbetween said transmitter and said distributor for transmitting auxiliaryservice signals, said means comprising a plurality of cam-controlledswitches and means for characterizing said service signals by conformityof their marking and spacing units to said fixed ratio, said system alsoincluding means operable bysaid service signal transmitting means forinterrupting the transmission of signals by either of the other two saidsignaling means during transmission of a service signal.

5. Station equipment for transmitting multiplex printing telegraph codesignals comprising a tape-controlled code signal transmitter,impulse-driven means connected to certain operating segments on amultiplex distributor for actu- 5 ating said transmitter and for feedingthe tape at a predetermined rate, a plurality of at least sevencode-composing members settable in accordance with a uniform number ofperforations in the tape for each code signal to be transmitted, saidmembers being adapted to be released periodically by said impulse-drivenmeans, an idletime signalling device comprising a relay having at leastthree movable contactors each associated with a front and a backcontact, each front contact being connected to a source of current, andeach back contact being connected to an appropriate one of saidcode-composing members, circuits connecting said movable contactors withappropriate segments on said multiplex distributor, and manuallyoperable means for interrupting the tape-feeding function of saidimpulse driven means while causing the relay of said idletime signallingdevice to assume and to maintain an operated condition.

6. Station equipment for transmitting multiplex printing telegraph codesignals comprising a tape-controlled code signal transmitter,impulse-driven means connected to certain operating segments on amultiplex distributor for actuating said transmitter and for feeding thetape at a predetermined rate, a plurality of at least sevencode-composing members settable in accordance with a uniform number ofperforations in the tape for each code signal to be transmitted, saidmembers being adapted to be released periodically by said impulse-drivenmeans, an auxiliarysignalling device comprising a pluralityof sets ofcode-element determining switches and cams for throwing said switches,each of said switches being of the double-throw type, manipulative meansfor initiating a desired movement of said cams, magnetically controlledescapement means for causing said cams to throw said switchespermutationally and sequentially and hence to cause a desired successionof service signals to be transmitted in place of signals initiated bysaid tape-controlled code-composing members, said switches beingseverally arranged while in a normal position to interconnect certain ofsaid code composing members with appropriate segments on said multiplexdistributor, said cams constituting means for characterizing each ofsaid service signals as having a fixed ratio between the number ofmarking elements and the number of spacing elements thereof, and meansincluding an off-normal switch operable by said manipulative means forshifting the connections of said operating segments on the distributorfrom said impulse driven means to said escapement means.

7. In a telegraph transmitting system, means including a perforated tapefor storing 7-unit code signals, a tape-controlled transmitter includinga distributor, means including a magnet for feeding said tape throughsaid transmitter at a cyclic rate which is synchronized with theoperation of said distributor, a tape supply source operable at anirregular speed, manipulative means having an escapement magnetassociated therewith for initiating service-signals, a differentialrelay having two windings opposingly connected in parallel circuits,both said windings being series-connected to said tape-feeding magnet,said relay having a make-before-break contact assembly which is adaptedto close a pulsating circuit from said distributor through one of therelay windings when said relay is de-magnetized, said contact assemblybeing further adapted to feed a constant current through the lastmentioned winding when said relay is mag netized, two circuit breakersboth in series with the other winding of said relay, one of said circuitbreakers being operable by the tape when subjected to a given take-up ofits slack, the other of said circuit breakers being operable by saidmanipulative means, said tape feeding magnet being subject to alocking-up control by said relay upon opening either one of said circuitbreakers, and means operable by said manipulative means for completingsaid pulsating circuit through said escapement magnet whenever a servicesignal is to be transmitted.

8. In a telegraph transmitting system a distributor having separatesegments for the respective code elements of uniform length codesignals, a tranic signal keying device, a servicesignal keying device,both said devices having circuit connections to said segments and meansfor causing selected 'l-unit code signals to be sent out through saiddistributor, an idle time keying device having means operable to composea characteristic I-unit code signal, additional circuit connectionsbetween certain of said segments and said idle time keying device, andmeans including a rela automatically effective during relatively longperiods between transmissions of traffic signals by said traffic signalkeying device for repeatedly sending out an idle-time signal 'hroughsaid additional circuit connections and the segments connected thereto.

9. In a telegraph system adapted to transmit 'l-unit code signals andcomprising a transmitter having a tape feeding device and an operatingimpulse circuit therefor fed with energizing current through adistributor, and comprising further an auxiliary service signallingdevice, the method of sending out tra fiic signals, auxiliary servicesignals, and idle-time signals alternatively, which comprises completingsaid operating impulse circuit through said tape feeding device as longas there is sufiicient slack in the tape to be utilized by thetransmitter, or until the transmitter is manually shut down,automatically interrupting said circuit and locking up the transmitterwhenever a shortage occurs in the supply of said tape, manually causingsaid circuit to be interrupted and the transmitter to be locked upwhenever a service signal is to be sent out, completing said operatingimpulse circuit in that event through said service signalling device,manually selecting a desired number of transmissions of said servicesignal to be made sequentially, manually effecting an automatic controlwhereby said idle-time signal is substituted for said traffic signalsduring any substantial period of shut-down of said transmitter, andcausing said idle-time signal to be sent out repeatedly and insynchronism with the cyclic operation of said distributor.

1i). Signal transmitting apparatus adapted for use in a synchronousprinting telegraph system comprising a line, a perforated tapecontrolled transmitter, an auxiliary signalling means, cyclicallyoperable means for controlling the operation of said transmitter and ofsaid auxiliary signalling means alternatively, manipulative means fortransferring the effects of said cyclically operable means from controlof said transmitter to control of said auxiliary signalling means for apredetermined time interval, an idletime signalling device adapted to beinterposed in circuit between said transmitter and said line, andmanipulative means for transferring the effects of said cyclicallyoperable means from control of said transmitter to control of saididletime signalling device for a period of indefinite duration.

11. In a telegraph transmitting system, a line, a distributor, threealternatively usable code signal composing devices each operable toimpress code signals through said distributor to said line, each of saidsignals being distinguishable from a stray signal by virtue of a fixednumerical ratio which is maintained between its marking and spacingunits, the first of said devices having a set of perforatedtape-controlled polarity reversing switches having at least seventongues corresponding respectively with the several units of a codesignal, the second of said devices having an idle time relay the backcontacts of which are connected to certain of the tongues of saidpolarity reversing switches and the front contacts of which are fed withmarking signal potential, means for jointly operating the tongues ofsaid relay from back-to-front contact circuit closure positions, thethird of said devices comprising a set of cams and switch tonguescontrolled thereby, each said tongue being movable by its cam between aback and a front contact, each of the last said back contacts beingconnected to a respective one of the tongues in one and the other of thetwo code signal composing devices first mentioned, and each of the lastsaid front contacts being fed with marking signal potential, meansoperable under control of the tape fed to the first said code signalcomposing device for actuating said relay, and manually operable meansfor disabling the first and second said code signal composing devicesand for operating said cams to compose a predetermined succession ofservice signals.

12. In a telegraph transmitting system, a line, a distributor, threealternatively usable code signal composing devices each operable toimpress code signals through said distributor to said line, each of saidsignals being distinguishable from a stray signal by virtue of a fixedratio which is maintained between its marking and spacing units, thefirst of said devices having a set of perforated tape-controlledpolarity reversing switches each under control of a different line ofperforations in the tape and each normally connected to an appropriatesegment on said distributor, an idle time signaling device constitutingthe second of said signal composing devices and comprising circuitconnections to said distributor, a manually operable service signalingdevice constituting the third of said signal composing devices andcomprising circuit connections to said distributor, means operable uponconnecting any one of said signal composing devices to said distributorfor disconnecting the others therefrom, and means for transferring thesource of signals as impressed upon said line-from one to another ofsaid signal composing devices while maintaining said distributorcontinuously rotative for synchronizing of a receiving distributortherewith.

JAMES A. SPENCER.

